Support material for laminate shaping, product laminate-shaped by using the same, and laminate-shaped product production method

ABSTRACT

A laminate shaping support material is provided which includes one of: a resin composition containing a polyvinyl alcohol resin having a primary hydroxyl group at its side chain, and having a heat of fusion of 10 to 30 J/g at its melting point (Embodiment (X)); and a resin composition containing a polyvinyl alcohol resin, and a block copolymer including a polymer block of an aromatic vinyl compound, at least one of a polymer block of a conjugated diene compound and a block of a hydrogenated conjugated diene compound, and a functional group reactive with a hydroxyl group (Embodiment (Y)). Therefore, the laminate shaping support material according to Embodiment (X), for example, is excellent in shape stability and adhesiveness to a model material. The laminate shaping support material according to Embodiment (Y) is excellent in peelability and forming stability.

The present application is a Continuation of U.S. application Ser. No.15/312,290, filed Nov. 18, 2016, which is a National stage ofInternational Patent Application No. PCT/JP2015/065334, filed May 28,2015, which claims priority to Japanese Application No. 2014-111373,filed May 29, 2014 and Japanese Application No. 2014-136886, filed Jul.2, 2014, the contents of which are expressly incorporated by referenceherein in their entireties.

TECHNICAL FIELD

The present invention relates to a laminate shaping support material tobe used for laminate shaping and thereafter removed (hereinaftersometimes referred to simply as “support material”) and a productlaminate-shaped by using the support material. The invention furtherrelates to a laminate-shaped product production method. Morespecifically, the invention relates to a laminate shaping supportmaterial which is excellent in shape stability, adhesiveness to a modelmaterial, peelability and forming stability.

The term “model material” means a material for the product to be shaped,and the term “support material” means a support-forming material whichfacilitates the shaping of the model material and is removed after theshaping in most cases.

BACKGROUND ART

The term “laminate shaping” means a method of shaping athree-dimensional product having a predetermined structure. A fluidmaterial is solidified immediately after being extruded, and furtherlaid over the solidified material, whereby the product is shaped. AUV-curing method, a fusion laminate method and the like are proposed forthe laminate shaping method. The fusion laminate method is widelyemployed because of the simplified structure of a laminate shapingdevice.

The term “support material” means a material which is used for thelaminate shaping of the three-dimensional product to complement theintended three-dimensional structure to fill an absent portion of thestructure. The three-dimensional product to be laminate-shaped has avariety of structural portions and, in the laminate shaping process,some of the structural portions cannot be shaped without support withother material. The support material is used for supporting thestructural portions of the three-dimensional product in the shapingprocess, and finally removed.

Conventionally, a variety of support materials for the laminate shapingare studied, which are classified into those that are dissolved away ina liquid after the shaping, those that are ground off after the shaping,and those that are blown off by a liquid or a gas after the shaping.

Where the three-dimensional product has a complicated shape, it isdifficult to grind off the support material without any damage to theproduct. The support material adapted to be blown off problematicallyhas an insufficient strength, failing to sufficiently support theproduct. To cope with these problems, a support material adapted to bedissolved away in a liquid is proposed (PTL 1).

Exemplary water-soluble resins proposed for use as a support material tobe washed away with water include an amorphous poly(2-ethyl-2-oxazoline)(PTL 2) and a polyvinyl alcohol (hereinafter abbreviated as PVA) (PTL3). Particularly, PTL 3 proposes that astyrene-ethylene-butylene-styrene block copolymer (SEBS) is added to anamorphous PVA to impart the PVA with flexibility. The amorphouswater-soluble resin is less liable to contract when being cooled to besolidified and, therefore, is excellent in shape reproducibility.

Further, a variety of model materials for shaping the three-dimensionalproduct are studied, and an acrylonitrile-butadiene-styrene (ABS) resinis mainly used in consideration of melt formability, heat stability andmechanical properties after solidification thereof.

RELATED ART DOCUMENT Patent Document

PTL 1: JP-A-2014-24329

PTL 2: JP-A-2002-516346

PTL 3: US-A-2011-0060445

SUMMARY OF INVENTION

However, the support materials hitherto proposed are liable to deformwhen a support material layer or a model material layer is laid over apreviously formed support material layer before the previous layer issufficiently cooled. Therefore, the support materials suffer fromunstable shape and insufficient adhesiveness to the model material. Thisproblematically reduces the shape reproducibility due to an offsetbetween the support material layer and the model material layer.Therefore, the support materials are unsatisfactory, and still requireimprovement.

Further, a method of entirely dissolving the support material toactually remove the support material is time-consuming. Therefore, amethod to be generally employed is such that, after the shaping, thesupport material is physically peeled off from the model material tosome extent and then a remaining portion of the support material isdissolved away. The amorphous PVA proposed as the support material inPTL 3 cannot be easily peeled off with difficulty in deformation afterthe solidification, so that the amount of the support material to bedissolved away is increased. The support material prepared by adding theSEBS to the amorphous PVA is soft and deformable, but is insufficient intoughness. Therefore, the support material cannot be successfully peeledoff, but is torn. Further, the affinity between the PVA resin and theSEBS is weak, so that the melt formability is unstable and the shapereproducibility is reduced in the laminate shaping.

Thus, the conventional support materials are unsatisfactory in theaforementioned aspects, still requiring improvement.

It is an object of the present invention to provide a laminate shapingsupport material improved in shape stability, adhesiveness to the modelmaterial, peelability and forming stability without the aforementionedproblems.

As a result of intensive studies in view of the foregoing, the inventorsof the present invention found that the aforementioned problems aresolved by using a resin composition (Embodiment (X)) containing a PVAresin having a heat of fusion of 10 to 30 J/g at its melting point andincluding a structural unit having a primary hydroxyl group at its sidechain (preferably, a PVA resin having a 1,2-diol structural unit at itsside chain wherein the structural unit having the primary hydroxyl groupat its side chain is a structural unit having a 1,2-diol structure atits side chain (hereinafter sometimes referred to simply as“1,2-diol-containing PVA resin”)) or by using a resin composition(Embodiment (Y)) containing a PVA resin and a block copolymer includinga polymer block of an aromatic vinyl compound, at least one of a polymerblock of a conjugated diene compound and a block of a hydrogenatedconjugated diene compound, and a functional group reactive with ahydroxyl group (hereinafter sometimes referred to simply as “blockcopolymer”), and attained the present invention.

It is assumed that these effects are based on the following mechanisms:

(1) Embodiment (X)

The heat of fusion of the PVA resin at the melting point is an indexindicating the crystallinity of the PVA resin. In order to ensure theshape stability, it is conventionally considered advantageous to use anamorphous water-soluble resin as the support material. However, thestudies conducted by the inventors reveal that, where the amorphoussupport material is used, the shape stability cannot be ensured. This isbecause, with a recent trend toward increase in laminate-shaping speed,thermal deformation is liable to occur when a support material layer ora model material layer is laid over a support material layer previouslyformed by melt-extruding the support material before the previoussupport material layer is sufficiently cooled. To cope with this, asupport material excellent in shape stability and adhesiveness to themodel material is designed by employing the PVA resin having a specificcrystallinity (i.e., a heat of fusion of 10 to 30 J/g at its meltingpoint) and including the structural unit having the primary hydroxylgroup at its side chain (particularly, including the 1,2-diol structuralunit at its side chain). Where the support material has insufficientadhesiveness to the model material, an offset occurs in an interfacebetween the support material and the model material, making itimpossible to ensure the shape reproducibility. Where the PVA resinhaving the primary hydroxyl group at its side chain (particularly, the1,2-diol-containing PVA resin) is used for the support material, incontrast, the support material has an improved affinity for the modelmaterial and hence higher adhesiveness to the model material to bethereby improved in shape reproducibility.

(2) Embodiment (Y)

The mechanism of the aforementioned effects is as follows. With the PVAresin and the block copolymer forming a sea-island structure, thesupport material per se is flexible and deformable. Further, the blockcopolymer has the functional group reactive with the hydroxyl group ofthe PVA resin. Therefore, when the support material is peeled off, asufficient adhesive force is provided in an interface between the blockcopolymer serving as an island component and the PVA resin serving asthe sea component in the support material. Thus, the support material isdeformed without cracking to be thereby removed from the model materialwithout fracture. Further, the block copolymer preferably has anaffinity for the PVA resin. Since the block copolymer has the functionalgroup reactive with the hydroxyl group of the PVA resin, the supportmaterial melt-extruded for the laminate shaping has an improved formingstability.

JP-A-2011-173998 proposes a latex which is prepared by melt-kneading aPVA and a thermoplastic styrene elastomer having a carboxylic acid groupor a derivative of the carboxylic acid group at its side chain anddispersing the thermoplastic styrene elastomer in water with the PVAresin of the resulting mixture dissolved in water. This literatureneither states that the resin composition (latex) containing the PVAresin and the thermoplastic styrene elastomer having the carboxylic acidgroup is usable as a support material for laminate shaping, nordiscloses physical properties of the resin composition required for thelaminate shaping and the formulation of the resin composition requiredfor the physical properties.

Further, JP-A-2011-74364 proposes a resin composition containing a PVApolymer, a block copolymer including a polymer block of an aromaticvinyl compound free from a carboxyl group and at least one of a polymerblock of a conjugated diene compound and a block of a hydrogenatedconjugated diene compound, and a block copolymer having a carboxylgroup. This literature mentions only the flexural fatigue resistance andthe gas barrier property of a film formed from the resin composition,but neither states that the resin composition is usable as a supportmaterial for laminate shaping, nor discloses physical properties of theresin composition required for the laminate shaping and the formulationof the resin composition required for the physical properties.

According to a first aspect of the present invention, there is provideda laminate shaping support material containing one of:

(X) a resin composition containing a polyvinyl alcohol resin including astructural unit having a primary hydroxyl group at its side chain, andhaving a heat of fusion of 10 to 30 J/g at its melting point (Embodiment(X)); and(Y) a resin composition containing a polyvinyl alcohol resin, and ablock copolymer including a polymer block of an aromatic vinyl compound,at least one of a polymer block of a conjugated diene compound and ablock of a hydrogenated conjugated diene compound, and a functionalgroup reactive with a hydroxyl group (Embodiment (Y)).

According to a second aspect of the present invention, there is provideda product laminate-shaped by using the laminate-shaping support materialof the first aspect.

According to a third aspect of the present invention, there is provideda laminate-shaped product production method including the steps of:alternately laying a layer of the laminate-shaping support material ofthe first aspect and a layer of a model material one on another in afluid state; solidifying the support material and the model material;and removing the support material.

The laminate shaping support material of Embodiment (X) of the presentinvention is excellent in shape stability and adhesiveness (adhesion) tothe model material.

The laminate shaping support material of Embodiment (Y) of the presentinvention is excellent in peelability and forming stability.

DESCRIPTION OF EMBODIMENTS

The present invention provides laminate shaping support materials, whichrespectively include resin compositions according to two differentembodiments. The laminate shaping support materials according to the twoembodiments of the present invention will hereinafter be described.

Embodiment (X)

The laminate shaping support material according to Embodiment (X)employs a resin composition (X) which contains a specific PVA resinincluding a structural unit having a primary hydroxyl group at its sidechain, and having a heat of fusion of 10 to 30 J/g at its melting point.

The specific PVA resin will hereinafter be described in detail.

[Specific PVA Resin]

The specific PVA resin to be used in Embodiment (X) includes thestructural unit having the primary hydroxyl group at its side chain. Thenumber of primary hydroxyl groups is typically 1 to 5, preferably 1 to2, particularly preferably 1. Further, the specific PVA resin preferablyhas a secondary hydroxyl group in addition to the primary hydroxylgroup.

Examples of the specific PVA resin include a PVA resin having a 1,2-diolstructural unit at its side chain, and a PVA resin having a hydroxyalkylgroup structural unit at its side chain. Particularly, the PVA resinhaving the 1,2-diol structural unit at its side chain is preferredbecause the resulting support material has an improved affinity for amodel material and higher adhesiveness to the model material.

In the specific PVA resin, the proportion (modification ratio) of thestructural unit having the primary hydroxyl group at its side chaindiffers depending upon the type of the structural unit, but typically0.1 to 10 mol %. If the modification ratio is excessively low, thesupport material tends to have a reduced adhesiveness to the modelmaterial. If the modification ratio is excessively high, the supportmaterial tends to have an excessively low crystallization speed,resulting in deformation during laminate shaping. Further, the supportmaterial tends to have a lower adhesive force with respect to the modelmaterial.

The specific PVA resin typically has an average polymerization degree of150 to 4000, preferably 200 to 2000 (as measured in conformity with JISK6726). If the average polymerization degree is excessively low, stableshaping tends to be difficult in the laminate shaping. If the averagepolymerization degree is excessively high, the resin composition tendsto have an excessively high viscosity, making it difficult to perform amelt-forming process.

The viscosity of an aqueous solution of the specific PVA resin issometimes employed as an index of the polymerization degree of the PVAresin. The 1,2-diol-containing PVA resin typically has a viscosity of1.5 to 20 mPa·s, preferably 2 to 12 mPa·s, particularly preferably 2.5to 8 mPa·s. If the viscosity is excessively low, stable shaping tends tobe difficult in the laminate shaping. If the viscosity is excessivelyhigh, the resin composition tends to have an excessively high viscosity,making it difficult to perform the melt-forming process.

The viscosity of the 1,2-diol-containing PVA resin herein means aviscosity of a 4 wt. % aqueous solution of the 1,2-diol-containing PVAresin measured at 20° C. in conformity with JIS K6726.

The specific PVA resin typically has a saponification degree of not lessthan 70 mol %, preferably not less than 80 mol %. If the saponificationdegree is excessively low, the shape stability tends to be reducedduring the laminate shaping.

The saponification degree is measured in conformity with JIS K6726.

Next, the PVA resin having the 1,2-diol structural unit at its sidechain will be described in detail.

A specific example of the PVA resin having the 1,2-diol structural unitat its side chain is a PVA resin having a 1,2-diol structural unitrepresented by the following general formula (1). Since the PVA thus hasthe 1,2-diol structural unit at its side chain, the support material isadvantageously improved in affinity for the model material. In thegeneral formula (1), R¹, R² and R³ are independently each a hydrogenatom or a C1 to C4 alkyl group, X is a single bond or a bonding chain,R⁴, R⁵ and R⁶ are independently each a hydrogen atom or a C1 to C4 alkylgroup.

wherein R¹, R² and R³ are independently each a hydrogen atom or a C1 toC4 alkyl group, X is a single bond or a bonding chain, R⁴, R⁵ and R⁶ areindependently each a hydrogen atom or a C1 to C4 alkyl group.

The proportion (modification ratio) of the 1,2-diol structural unitrepresented by the general formula (1) for the 1,2-diol-containing PVAresin is typically 0.1 to 10 mol %, preferably 0.5 to 9 mol %, morepreferably 2 to 8 mol %, particularly preferably 3 to 8 mol %. If themodification ratio is excessively low, the support material tends tohave a reduced adhesiveness to the model material. If the modificationratio is excessively high, the support material tends to have anexcessively low crystallization speed, resulting in deformation duringthe laminate shaping. Further, the support material tends to have alower adhesive force with respect to the model material. Like anordinary PVA resin, the 1,2-diol-containing PVA resin includes a vinylalcohol structural unit and an unsaponified vinyl ester structural unit,in addition to the 1,2-diol structural unit.

In the 1,2-diol structural unit represented by the general formula (1),R¹ to R³ and R⁴ to R⁶ are preferably all hydrogen atoms with the primaryhydroxyl group being present at a side chain terminal for improvement ofthe adhesiveness to the model material. However, some of R¹ to R³ and R⁴to R⁶ may be substituted with a C1 to C4 alkyl group, as long as theproperties of the resin are not significantly impaired. Examples of theC1 to C4 alkyl group include a methyl group, an ethyl group, a n-propylgroup, an isopropyl group, a n-butyl group, an isobutyl group and atert-butyl group, which may have a substituent such as a halogen atom, ahydroxyl group, an ester group, a carboxylic acid group or a sulfonicacid group as required.

In the 1,2-diol structural unit represented by the general formula (1),X is typically a single bond. For heat stability, X is most preferably asingle bond, but may be a bonding chain as long as the effects of thepresent invention are not impaired. The bonding chain is notparticularly limited, but examples of the bonding chain includehydrocarbons such as alkylenes, alkenylenes, alkynylenes, phenylene andnaphthylene (which may be substituted with a halogen such as fluorine,chlorine or bromine), —O—, —(CH₂O)_(m)—, —(OCH₂)_(m)—, —(CH₂O)_(m)CH₂—,—CO—, —COCO—, —CO(CH₂)_(m)CO—, —CO(C₆H₄)CO—, —S—, —CS—, —SO—, —SO₂—,—NR—, —CONR—, —NRCO—, —CSNR—, —NRCS—, —NRNR—, —HPO₄—, —Si(OR)₂—,—OSi(OR)₂—, —OSi(OR)₂O—, —Ti(OR)₂—, —OTi(OR)₂—, —OTi(OR)₂O—, —Al(OR)—,—OAl(OR)— and —OAl(OR)O—, wherein Rs are independently each a givensubstituent, preferably a hydrogen atom or an alkyl group, and m is anatural number. Among these, the bonding chain is preferably an alkylenegroup having a carbon number of not greater than 6 for stability duringproduction or during use, particularly preferably a methylene group or—CH₂OCH₂—.

The 1,2-diol-containing PVA resin typically has an averagepolymerization degree of 150 to 4000, preferably 200 to 2000,particularly preferably 250 to 800 (as measured in conformity with JISK6726). If the average polymerization degree is excessively low, stableshaping tends to be difficult in the laminate shaping. If the averagepolymerization degree is excessively high, the melt forming tends to bedifficult.

The viscosity of an aqueous solution of the PVA resin is sometimesemployed as an index of the polymerization degree of the PVA resin. The1,2-diol-containing PVA resin typically has a viscosity of 1.5 to 20mPa·s, preferably 2 to 12 mPa·s, particularly preferably 2.5 to 8 mPa·s.If the viscosity is excessively low, stable shaping tends to bedifficult in the laminate shaping. If the viscosity is excessively high,the resin composition tends to have an excessively high viscosity,making it difficult to perform the melt-forming process.

The viscosity of the 1,2-diol-containing PVA resin herein means aviscosity of a 4 wt. % aqueous solution of the 1,2-diol-containing PVAresin measured at 20° C. in conformity with JIS K6726.

The 1,2-diol-containing PVA resin typically has a saponification degreeof not less than 70 mol %, preferably 75 to 99.7 mol %, particularlypreferably 87 to 99.5 mol %. If the saponification degree is excessivelylow, the shape stability tends to be reduced during the laminateshaping.

The saponification degree is measured in conformity with JIS K6726.

The main chain of the PVA resin mainly has 1,3-diol bonds, and theproportion of 1,2-diol bonds in the main chain is about 1.5 to about 1.7mol %. The PVA resin to be used may contain the 1,2-diol bonds in aproportion increased to 2.0 to 3.5 mol % by increasing thepolymerization temperature in the polymerization of the vinyl estermonomer.

In Embodiment (X), the PVA resin may be a copolymer obtained bycopolymerization with a small amount of other comonomer, as long as theproperties of the resin are not significantly influenced. Examples ofthe comonomer include: olefins such as ethylene, propylene, isobutylene,α-octene, α-dodecene and α-octadecene; unsaturated acids such as acrylicacid, methacrylic acid, crotonic acid, maleic acid, maleic anhydride anditaconic acid, and salts, monoalkyl and dialkyl esters thereof; nitrilessuch as acrylonitrile and methacrylonitrile; amides such as acrylamideand methacrylamide; olefin sulfonic acids such as ethylene sulfonicacid, allyl sulfonic acid and methallyl sulfonic acid, and saltsthereof; alkyl vinyl ethers, N-acrylamide methyl trimethyl ammoniumchloride, allyl trimethylammonium chloride, dimethylallyl vinyl ketone,N-vinylpyrrolidone, vinyl chloride and vinylidene chloride;polyoxyalkylene (meth)allyl ethers such as polyoxyethylene (meth)allylethers and polyoxypropylene (meth)allyl ethers; polyoxyalkylene(meth)acrylates such as polyoxyethylene (meth)acrylates andpolyoxypropylene (meth)acrylates; polyoxyalkylene (meth)acrylamides suchas polyoxyethylene (meth)acrylamides and polyoxypropylene(meth)acrylamides; and hydroxyl group-containing α-olefins such aspolyoxyethylene (1-(meth)acrylamide-1,1-dimethylpropyl) esters,polyoxyethylene vinyl ethers, polyoxypropylene vinyl ethers,polyoxyethylene allylamines, polyoxypropylene allylamines,polyoxyethylene vinylamines, polyoxypropylene vinylamines, 3-buten-1-ol,4-penten-1-ol and 5-hexen-1-ol, and acylation products and otherderivatives thereof.

The 1,2-diol-containing PVA resin typically has a melting point of 120°C. to 230° C., preferably 150° C. to 220° C., particularly preferably160° C. to 190° C. If the melting point is excessively high, the resinis liable to be deteriorated with the need for increasing the processtemperature in the laminate shaping. If the melting point is excessivelylow, the shape stability tends to be reduced during the laminateshaping.

In Embodiment (X), the PVA resin including the structural unit havingthe primary hydroxyl group at its side chain, preferably the1,2-diol-containing PVA resin, is required to have a heat of fusion of10 to 30 J/g, preferably 15 to 27 J/g, particularly preferably 20 to 25J/g, at its melting point. If the heat of fusion is excessively high,the support material tends to significantly shrink during solidificationthereof and hence have poorer shape stability. If the heat of fusion isexcessively low, a layer of the support material tends to deform whenthe next layer is formed in the laminate shaping.

The method of measuring the heat of fusion at the melting point will bedescribed below in detail. A differential scanning calorimeter of aninput compensation type is used for the measurement. The measurement isstarted at a measurement starting temperature that is lower than themelting point by not less than 50° C., typically about −30° C. to about30° C., and the measurement temperature is increased from themeasurement starting temperature at a temperature increase rate of 10°C./min to a target temperature that is higher by about 30° C. than themelting point so as prevent the thermal decomposition of the resin.Thereafter, the measurement temperature is reduced at a temperaturedecrease rate of 10° C./min to the measurement starting temperature, andthen increased again at a temperature increase rate of 10° C./min to atarget temperature that is higher by about 30° C. than the meltingpoint. The heat ΔH (J/g) of fusion is calculated based on a heatabsorption peak area observed at the melting point in the secondtemperature increase. The first target temperature and the second targettemperature are not necessarily required to be the same. The amount of asample to be used for the measurement differs depending upon themeasurement apparatus and the size of the container (pan) to be used,but typically about 5 to about 10 mg. If the amount of the sample isexcessively great or excessively small, the error of the measurement ofthe heat of fusion is increased. What is important for the calculationof the heat ΔH of fusion is how to draw a base line. In an analysischart, an abscissa axis is defined as the axis of the temperature, andthe base line is defined as a straight line connecting a point A at atemperature higher by 5° C. than an end point of the absorption peak ofa DSC curve and a point B at a temperature lower by 40° C. than the apexof the heat absorption peak of the DSC curve. The heat ΔH of fusion iscalculated based on an area enclosed by the base line and the heatabsorption peak.

The production method of the 1,2-diol-containing PVA resin to beadvantageously used in Embodiment (X) is not particularly limited, butexamples of the production method include: (i) a method in which acopolymer of a vinyl ester monomer and a compound represented by thefollowing general formula (2) is saponified; (ii) a method in which acopolymer of a vinyl ester monomer and a compound represented by thefollowing general formula (3) is saponified and decarbonated; and (iii)a method in which a copolymer of a vinyl ester monomer and a compoundrepresented by the following general formula (4) is saponified anddeketalized. The 1,2-diol-containing PVA resin may be produced, forexample, by a method described in paragraphs [0014] to [0037] inJP-A-2008-163179.

In the above general formulae (2), (3) and (4), R¹, R², R³, x, R⁴, R⁵and R⁶ are the same as those for the general formula (1), and R⁷ and R⁸are independently each a hydrogen atom or R⁹—CO— wherein R⁹ is a C1 toC4 alkyl group. R¹⁰ and R¹¹ are independently each a hydrogen atom or aC1 to C4 alkyl group.

[Laminate Shaping Support Material According to Embodiment (X)]

The laminate shaping support material according to Embodiment (X) is aresin composition which contains the PVA resin including the structuralunit having the primary hydroxyl group at its side chain, preferably the1,2-diol-containing PVA resin, as a main component. The support materialis generally formed into a strand, which is wound around a reel and, inthis state, set in a laminate shaping apparatus. Therefore, the supportmaterial is required to have flexibility and toughness that aresufficient to prevent breakage when being wound around the reel. Forpractical use, a flexible component is preferably added to the resincomposition. In the support material according to Embodiment (X), thePVA resin including the structural unit having the primary hydroxylgroup at its side chain, preferably the 1,2-diol-containing PVA resin,is typically present in a proportion of 50 to 100 wt. %, preferably 55to 95 wt. %, particularly preferably 60 to 90 wt. %, based on theoverall weight of the support material. If the proportion of the PVAresin is excessively small, the support material tends to be poorer indissolvability. If the proportion of the PVA resin is excessively great,the support material tends to be poorer in flexibility.

A thermoplastic resin is usable as the flexible component. Examples ofthe thermoplastic resin include polyolefin resins, polyester resins,polyamide resins, acryl resins, polyvinyl resins (polyvinyl acetates,polyvinyl chlorides and the like) and thermoplastic elastomers.

Examples of the thermoplastic elastomers include urethane elastomers,ester elastomers and styrene elastomers. A block copolymer including apolymer block of an aromatic vinyl compound, and at least one of apolymer block of a conjugated diene compound and a block of ahydrogenated conjugated diene compound is preferably used as thethermoplastic elastomer. The block copolymer preferably has a functionalgroup reactive with a hydroxyl group to impart the support material withtoughness, and the functional group is particularly preferably an acid.The block copolymer preferably has an acid value of 1 to 10 mgCH₃CONa/g, particularly preferably 2 to 5 mg CH₃CONa/g. The acid valueis measured by a neutralization titration method by which an alkaliconsumption required for neutralization is determined.

The proportion of the flexible component is preferably 5 to 50 wt. %,more preferably 10 to 40 wt. %, particularly preferably 15 to 35 wt. %,based on the weight of the PVA resin including the structural unithaving the primary hydroxyl group at its side chain.

A plasticizer may be added to the support material according toEmbodiment (X). In order to stabilize the shape of the support materialaccording to Embodiment (X), the proportion of the plasticizer ispreferably minimized, and preferably not greater than 20 wt. %, morepreferably not greater than 10 wt. %, particularly preferably notgreater than 1 wt. %, especially preferably not greater than 0.1 wt. %.

In addition to the aforementioned component, known additives such as afiller, an antioxidant, a colorant, an antistatic agent, a UV absorberand a lubricant may be added to the resin composition as required.

The support material according to Embodiment (X) has a melt flow rate of0.2 to 25 g/10 min, particularly preferably 1.0 to 15 g/min, morepreferably 2.0 to 10 g/10 min, as measured at 210° C. with a load of2160 g in conformity with JIS K7210 as an index of the melt viscosity.If the melt viscosity is excessively low, the support material is liableto drip from a nozzle during the shaping, preventing proper shaping. Ifthe melt viscosity is excessively high, the nozzle is liable to beclogged.

The production method of the support material of Embodiment (X) for thelaminate shaping includes the steps of: mixing the aforementionedingredients in predetermined proportions; kneading the resulting mixturein a melted state with heating; extruding the mixture into a strand;cooling the strand; and winding the strand around a reel. Morespecifically, the aforementioned ingredients are fed as a mixture orseparately into a single-screw or multi-screw extruder, heat-melted andkneaded, and extruded from a single-hole or multi-hole strand die into a1.5- to 3.0-mm diameter strand, which is in turn cooled with air or withwater to be solidified and then wound around the reel. The strand isrequired to have a stable diameter and have flexibility and toughnesssufficient to prevent breakage even if being wound around the reel.Further, the strand is required to have rigidity sufficient to ensureproper feed-out thereof to a head without delay in the laminate shaping.

Embodiment (Y)

The laminate shaping support material according to Embodiment (Y)employs a resin composition (Y) which contains a PVA resin, and a blockcopolymer including a polymer block of an aromatic vinyl compound, atleast one of a polymer block of a conjugated diene compound and a blockof a hydrogenated conjugated diene compound, and a functional groupreactive with a hydroxyl group.

[PVA Resin]

First, the PVA resin to be used in Embodiment (Y) will be described.

The PVA resin is a resin mainly including a vinyl alcohol structuralunit and prepared by copolymerizing a vinyl ester monomer andsaponifying the resulting polyvinyl ester resin. The PVA resin includesthe vinyl alcohol structural unit in a proportion corresponding to asaponification degree, and includes an unsaponified vinyl esterstructural unit.

Examples of the vinyl ester monomer include vinyl formate, vinylacetate, vinyl propionate, vinyl valerate, vinyl butyrate, vinylisobutyrate, vinyl pivalate, vinyl caprate, vinyl laurate, vinylstearate, vinyl benzoate and vinyl versatate, among which vinyl acetateis preferably used for economy.

The PVA resin to be used in Embodiment (Y) typically has an averagepolymerization degree of 150 to 4000, preferably 200 to 2000,particularly preferably 250 to 800, further preferably 300 to 600 (asmeasured in conformity with JIS K6726).

If the average polymerization degree is excessively low, stable shapingtends to be difficult in the laminate shaping. If the averagepolymerization degree is excessively high, the resin composition tendsto have an excessively high viscosity, making it difficult to performthe melt-forming process.

The viscosity of an aqueous solution of the PVA resin is sometimesemployed as an index of the polymerization degree of the PVA resin. Theaqueous solution of the PVA resin to be used in Embodiment (Y) typicallyhas a viscosity of 1.5 to 20 mPa·s, preferably 2 to 12 mPa·s,particularly preferably 2.5 to 8 mPa·s. If the viscosity is excessivelylow, stable shaping tends to be difficult in the laminate shaping. Ifthe viscosity is excessively high, the resin composition tends to havean excessively high viscosity, making it difficult to perform themelt-forming process.

As in Embodiment (X), the viscosity of the aqueous solution of the PVAresin herein means a viscosity of a 4 wt. % aqueous solution of the PVAresin measured at 20° C. in conformity with JIS K6726.

The PVA resin to be used in Embodiment (Y) typically has asaponification degree of not less than 70 mol %, preferably 75 to 99.7mol %, particularly preferably 85 to 99.5 mol %. If the saponificationdegree is excessively low, the PVA resin tends to have a reducedaffinity for the block copolymer, thereby reducing the shape stabilityin the laminate shaping.

The saponification degree is measured in conformity with JIS K6726.

The PVA resin typically has a melting point of 120° C. to 230° C.,preferably 150° C. to 220° C., particularly preferably 190° C. to 210°C. If the melting point is excessively high, the resin is liable to bedeteriorated with the need for increasing the process temperature in thelaminate shaping. If the melting point is excessively low, the shapestability tends to be reduced during the laminate shaping.

The main chain of the ordinary PVA resin mainly has 1,3-diol bonds, andthe proportion of 1,2-diol bonds in the main chain is about 1.5 to about1.7 mol %. The proportion of the 1,2-diol bonds, which can be increasedby increasing the polymerization temperature for the polymerization ofthe vinyl ester monomer, is preferably not less than 1.8 mol %, morepreferably 2.0 to 3.5 mol % for improvement of the affinity for theblock copolymer.

In Embodiment (Y), a PVA resin prepared by copolymerizing a comonomer inthe preparation of the vinyl ester resin and saponifying the resultingvinyl ester resin, and a modified PVA resin prepared by introducing afunctional group into an unmodified PVA by a post modification reactionare usable as the PVA resin. The modification degree of the PVA resin isgenerally not greater than 20 mol % so that the PVA resin has sufficientwater solubility.

Examples of the comonomer to be used for the copolymerization with thevinyl ester monomer include: olefins such as ethylene, propylene,isobutylene, α-octene, α-dodecene and α-octadecene; unsaturated acidssuch as acrylic acid, methacrylic acid, crotonic acid, maleic acid,maleic anhydride and itaconic acid, and salts, monoalkyl and dialkylesters thereof; nitriles such as acrylonitrile and methacrylonitrile;amides such as acrylamide and methacrylamide; olefin sulfonic acids suchas ethylene sulfonic acid, allyl sulfonic acid and methallyl sulfonicacid, and salts thereof; alkyl vinyl ethers, N-acrylamide methyltrimethylammonium chloride, allyl trimethylammonium chloride,dimethylallyl vinyl ketone, N-vinylpyrrolidone, vinyl chloride,vinylidene chloride; polyoxyalkylene (meth)allyl ethers such aspolyoxyethylene (meth)allyl ethers and polyoxypropylene (meth)allylethers; polyoxyalkylene (meth)acrylates such as polyoxyethylene(meth)acrylates and polyoxypropylene (meth)acrylates; polyoxyalkylene(meth)acrylamides such as polyoxyethylene (meth)acrylamides andpolyoxypropylene (meth)acrylamides; and hydroxyl group-containingα-olefins such as polyoxyethylene(1-(meth)acrylamide-1,1-dimethylpropyl) esters, polyoxyethylene vinylethers, polyoxypropylene vinyl ethers, polyoxyethylene allylamines,polyoxypropylene allylamines, polyoxyethylene vinylamines,polyoxypropylene vinylamines, 3-buten-1-ol, 4-penten-1-ol and5-hexen-1-ol, and acylation products and other derivatives thereof.

Examples of the PVA resin containing the functional group introducedtherein by the post reaction include a PVA resin having an acetoacetylgroup introduced therein by a reaction with a diketene, a PVA resinhaving a polyalkylene oxide group introduced therein by a reaction withethylene oxide, a PVA resin having a hydroxyalkyl group introducedtherein by a reaction with an epoxy compound or the like, and a PVAresin prepared by a reaction with an aldehyde compound having afunctional group.

The modification degree of the modified PVA resin, i.e., the proportionof a structural unit derived from the comonomer in the copolymer or theproportion of the functional group introduced in the PVA resin by thepost reaction, cannot be uniquely defined because the physicalproperties of the modified PVA resin significantly differ depending uponthe type of the compound to be used for the modification, but themodification degree is typically 0.1 to 20 mol %, particularlypreferably 0.5 to 12 mol %.

Among these modified PVA resins, a PVA resin including a structural unithaving a primary hydroxyl group at its side chain is preferably used inEmbodiment (Y). The number of primary hydroxyl groups is typically 1 to5, preferably 1 to 2, particularly preferably 1. The PVA resinpreferably has a secondary hydroxyl group in addition to the primaryhydroxyl group.

Examples of the PVA resin including the structural unit having theprimary hydroxyl group at its side chain include a PVA resin including a1,2-diol structural unit at its side chain, and a PVA resin including ahydroxyalkyl group structural unit at its side chain, among which thePVA resin including the 1,2-diol structural unit at its side chain(hereinafter sometimes referred to simply as “1,2-diol-containing PVAresin” as in Embodiment (X)) is preferred because of its higher affinityfor the block copolymer. A PVA resin including a 1,2-diol structuralunit represented by the following general formula (1) at its side chainis preferred as the 1,2-diol-containing PVA resin because of a higherreactivity between the hydroxyl group of the block copolymer and thefunctional group reactive with the hydroxyl group.

wherein R¹, R² and R³ are independently each a hydrogen atom or a C1 toC4 alkyl group, X is a single bond or a bonding chain, and R⁴, R⁵ and R⁶are independently each a hydrogen atom or a C1 to C4 alkyl group.

The proportion (modification ratio) of the 1,2-diol structural unitrepresented by the general formula (1) for the 1,2-diol-containing PVAresin is typically 0.5 to 12 mol %, preferably 2 to 8 mol %, morepreferably 3 to 8 mol %. If the modification ratio is excessively low,the PVA resin tends to have a lower reactivity with the functional groupof the block copolymer. If the modification ratio is excessively high,the support material tends to have an excessively low crystallizationspeed, resulting in deformation during the laminate shaping.

Like an ordinary PVA resin, the 1,2-diol-containing PVA resin includes avinyl alcohol structural unit and an unsaponified vinyl ester structuralunit, in addition to the 1,2-diol structural unit.

In the 1,2-diol structural unit represented by the general formula (1),R¹ to R³ and R⁴ to R⁶ are preferably all hydrogen atoms with the primaryhydroxyl group being present at a side chain terminal for furtherimprovement of the reactivity with the functional group of the blockcopolymer. However, some of R¹ to R³ and R⁴ to R⁶ may be substitutedwith a C1 to C4 alkyl group, as long as the properties of the resin arenot significantly impaired. Examples of the C1 to C4 alkyl group includea methyl group, an ethyl group, a n-propyl group, an isopropyl group, an-butyl group, an isobutyl group and a tert-butyl group, which may havea substituent such as a halogen atom, a hydroxyl group, an ester group,a carboxylic acid group or a sulfonic acid group as required.

In the 1,2-diol structural unit represented by the general formula (1),X is most preferably a single bond for heat stability and stabilityunder higher temperature conditions or acidic conditions, but may be abonding chain as long as the effects of the present invention are notimpaired. Examples of the bonding chain include hydrocarbons such asalkylenes, alkenylenes, alkynylenes, phenylene and naphthylene (whichmay be substituted with a halogen such as fluorine, chlorine orbromine), —O—, —(CH₂O)_(m)—, —(OCH₂)_(m)—, —(CH₂O)_(m)CH₂—, —CO—,—COCO—, —CO(CH₂)_(m)CO—, —CO(C₆H₄)CO—, —S—, —CS—, —SO—, —SO₂—, —NR—,—CONR—, —NRCO—, —CSNR—, —NRCS—, —NRNR—, —HPO₄—, —Si(OR)₂—, —OSi(OR)₂—,—OSi(OR)₂O—, —Ti(OR)₂—, —OTi(OR)₂—, —OTi(OR)₂O—, —Al(OR)—, —OAl(OR)—and—OAl(OR)O—, wherein Rs are independently each a given substituent,preferably a hydrogen atom or an alkyl group, and m is an integer of 1to 5. Among these, the bonding chain is preferably an alkylene grouphaving a carbon number of not greater than 6 for stability duringproduction or during use, particularly preferably a methylene group or—CH₂OCH₂—.

The production method of the PVA resin having the 1,2-diol structuralunit at its side chain is not particularly limited, but preferredexamples of the production method include: (i) a method in which acopolymer of a vinyl ester monomer and a compound represented by thefollowing general formula (2) is saponified; (ii) a method in which acopolymer of a vinyl ester monomer and a compound represented by thefollowing general formula (3) is saponified and decarbonated; and (iii)a method in which a copolymer of a vinyl ester monomer and a compoundrepresented by the following general formula (4) is saponified anddeketalized. The PVA resin may be produced, for example, by a methoddescribed in paragraphs [0014] to [0037] in JP-A-2008-163179.

In the above general formulae (2), (3) and (4), R¹, R², R³, X, R⁴, R⁵and R⁶ are the same as those for the general formula (1), and R⁷ and R⁸are independently each a hydrogen atom or R⁹—CO— wherein R⁹ is a C1 toC4 alkyl group. R¹⁰ and R¹¹ are independently each a hydrogen atom or aC1 to C4 alkyl group.

The PVA resin to be used in Embodiment (Y) may be a single type of PVAresin or a mixture of two or more types of PVA resins. In the lattercase, the aforementioned unmodified PVAs may be used in combination, orany of the unmodified PVAs and the PVA resin having the structural unitrepresented by the above general formula (1) may be used in combination.Further, PVA resins each having the structural unit represented by theabove general formula (1) and having different saponification degrees,different polymerization degrees and different modification degrees maybe used in combination, or any of the unmodified PVAs or any of the PVAresins having the structural unit represented by the above generalformula (1) and other modified PVA resin may be used in combination.

[Block Copolymer]

The support material according to Embodiment (Y) contains the PVA resinand, in addition, the block copolymer including the polymer block of thearomatic vinyl compound, at least one of the polymer block of theconjugated diene compound and the block of the hydrogenated conjugateddiene compound, and the functional group reactive with the hydroxylgroup.

The block copolymer to be used in Embodiment (Y) will be described.

The block copolymer to be used in Embodiment (Y) includes the polymerblock of the aromatic vinyl compound (typified by styrene) as a hardsegment, and the polymer block of the conjugated diene compound, ahydrogenated block obtained by hydrogenating some or all of remainingdouble bonds of the polymer block of the conjugated diene compound or apolymer block of isobutylene as a soft segment.

In Embodiment (Y), the block copolymer particularly preferably has thefunctional group reactive with the hydroxyl group at its side chain.More specifically, the block copolymer preferably has a carboxylic acidgroup or a derivative of the carboxylic acid group.

Where the hard segment is expressed by A and the soft segment isexpressed by B, the block copolymer may be a diblock copolymerrepresented by A-B, a triblock copolymer represented by A-B-A or B-A-B,or a polyblock copolymer including segments A and B alternatelyarranged. The block copolymer may have a straight structure, a branchedstructure or a star structure. The block copolymer is preferably astraight triblock copolymer represented by A-B-A from the viewpoint ofkinetic properties.

Examples of a monomer to be used for formation of the polymer block ofthe aromatic vinyl compound as the hard segment include styrene;alkylstyrenes such as α-methylstyrene, β-methylstyrene, o-methylstyrene,m-methylstyrene, p-methylstyrene, t-butylstyrene, 2,4-dimethylstyreneand 2,4,6-trimethylstyrene; halogenated styrenes such asmonofluorostyrene, difluorostyrene, monochlorostyrene anddichlorostyrene; methoxystyrene; vinyl compounds such asvinylnaphthalene, vinylanthracene, indene and acetonaphthylene having anaromatic ring other than a benzene ring, and their derivatives. Thepolymer block of the aromatic vinyl compound may be a homopolymer blockof a single monomer selected from the aforementioned monomers or acopolymer block of plural monomers selected from the aforementionedmonomers. However, a styrene homopolymer block is preferred.

The polymer block of the aromatic vinyl compound may be a copolymerblock formed by copolymerization with a small amount of a monomer otherthan the aromatic vinyl compound, as long as the effects of the presentinvention are not impaired. Examples of the other monomer includeolefins such as butene, pentene and hexene; diene compounds such asbutadiene and isoprene; vinyl ether compounds such as methyl vinylether; and allyl ether compounds. The copolymerization ratio istypically 10 mol % of the overall polymer block.

The polymer block of the aromatic vinyl compound in the block copolymertypically has a weight average molecular weight of 10,000 to 300,000,particularly preferably 20,000 to 200,000, further preferably 50,000 to100,000.

Examples of the monomer to be used for formation of the polymer block asthe soft segment include conjugated diene compounds such as1,3-butadiene, isoprene (2-methyl-1,3-butadiene),2,3-dimethyl-1,3-butadiene and 1,3-pentadiene, and isobutylene, whichmay be used alone or in combination. The polymer block is preferably ahomopolymer block or a copolymer block of isoprene, butadiene and/orisobutylene. Particularly, the polymer block is preferably a homopolymerof butadiene or isobutylene.

The polymer block of the conjugated diene compound has a plurality ofbonding arrangements depending upon the polymerization. In the case ofbutadiene, for example, a butadiene unit having 1,2-bonds(—CH₂—CH(CH═CH₂)—) and a butadiene unit having 1,4-bonds(—CH₂—CH═CH—CH₂—) are formed. The formation ratio of the diene unitsvaries depending upon the type of the conjugated diene compound, andcannot be uniquely defined. In the case of butadiene, the 1,2-bondformation ratio is typically 20 to 80 mol %.

By hydrogenating some or all of the remaining double bonds of thepolymer block of the conjugated diene compound, the heat resistance andthe weather resistance of the thermoplastic styrene elastomer can beimproved. At this time, the hydrogenation ratio is preferably not lessthan 50 mol %, particularly preferably not less than 70 mol %.

For example, the hydrogenation converts the butadiene unit having the1,2-bonds into a butylene unit (—CH₂—CH(CH₂—CH₃)—), and converts thebutadiene unit having the 1,4-bonds into two continuous ethylene units(—CH₂—CH₂—CH₂—CH₂—). Generally, the former unit is preferentiallyformed.

The polymer block serving as the soft segment may be a copolymer blockformed by copolymerization with a small amount of a monomer other thanthe aforementioned monomers. Examples of the other monomer includearomatic vinyl compounds such as styrene, olefins such as butene,pentene and hexene, vinyl ether compounds such as methyl vinyl ether,and allyl ether compounds. The copolymerization ratio of the othermonomer is generally not greater than 10 mol % of the overall polymerblock.

The polymer block of the conjugated diene compound or isobutylene in theblock copolymer typically has a weight average molecular weight of10,000 to 300,000, particularly preferably 20,000 to 200,000, furtherpreferably 50,000 to 100,000.

As described above, the block copolymer to be used in Embodiment (Y) ofthe present invention includes the polymer block of the aromatic vinylcompound as the hard segment, and the polymer block of the conjugateddiene compound or the polymer block obtained by hydrogenating some orall of the remaining double bonds of the conjugated diene compound andthe polymer block of isobutylene as the soft segment. Typical examplesof the block copolymer include a styrene/butadiene block copolymer (SBS)prepared by using styrene and butadiene as ingredients, astyrene/butadiene/butylene block copolymer (SBBS) obtained byhydrogenating side chain double bonds of the butadiene structural unitof the SBS, a styrene/ethylene/butylene block copolymer (SEBS) obtainedby hydrogenating main chain double bonds, a styrene/isoprene blockcopolymer (SIPS) prepared by using styrene and isoprene as ingredients,and a styrene/isobutylene block copolymer (SIBS) prepared by usingstyrene and isobutylene as ingredients. Particularly, the SEBS and theSIBS are preferably used, which are excellent in heat stability andweather resistance.

The weight ratio between the polymer block of the aromatic vinylcompound serving as the hard segment and the polymer blocks serving asthe soft segment in the block copolymer is typically 10/90 to 70/30,particularly preferably 20/80 to 50/50. If the proportion of the polymerblock of the aromatic vinyl compound is excessively great or excessivelysmall, the balance between the flexibility and the elasticity of theblock copolymer is deteriorated. As a result, the support material isinsufficient in peelability and other properties.

The block copolymer can be produced by preparing the block copolymerincluding the polymer block of the aromatic vinyl compound and thepolymer block of the conjugated diene compound or isobutylene and, asrequired, hydrogenating double bonds of the polymer block of theconjugated diene compound.

A known method may be used for the production of the block copolymerincluding the polymer block of the aromatic vinyl compound and thepolymer block of the conjugated diene compound or isobutylene. Forexample, the production of the block copolymer may be achieved bysequentially polymerizing the aromatic vinyl compound and the conjugateddiene compound or isobutylene in an inactive organic solvent with theuse of an alkyllithium compound or the like as an initiator.

A known method may be used for the hydrogenation of the block copolymerincluding the polymer block of the aromatic vinyl compound and thepolymer block of the conjugated diene compound. For example, thehydrogenation may be achieved by using a reducing agent such as ahydrogenated boron compound, or by using a metal catalyst such asplatinum, palladium or Raney nickel for hydrogen reduction.

A characteristic feature of the present invention is that the blockcopolymer to be used in Embodiment (Y) has the functional group reactivewith the hydroxyl group at its side chain. The functional group ispreferably a carboxylic acid. The support material produced by using theblock copolymer having the functional group reactive with the hydroxylgroup at its side chain is excellent particularly in peelability andforming stability.

The amount of the carboxylic acid to be contained in the block copolymeris typically 0.5 to 20 mg CH₃ONa/g, particularly preferably 1 to 10 mgCH₃ONa/g, further preferably 1.5 to 3 mg CH₃ONa/g, which is measured asacid value by a titration method.

If the acid value is excessively low, it will be impossible tosufficiently provide the effect of introducing the functional group intothe block copolymer. If the acid value is excessively high, the supportmaterial tends to have an excessively high melt viscosity due to acrosslinking reaction.

A known method may be used for the introduction of the carboxylicacid-containing functional group into the block copolymer. Preferredexamples of the method include a method in which an α, β-unsaturatedcarboxylic acid or its derivative is copolymerized in the production ofthe block copolymer (i.e., during the copolymerization), and a method inwhich an α, β-unsaturated carboxylic acid or its derivative is added tothe block copolymer after the production of the block copolymer.Specific examples of the addition method include a method in which theaddition is achieved by a radical reaction in a solution in the presenceor absence of a radical initiator, and a method in which the blockcopolymer and the α,β-unsaturated carboxylic acid or its derivative aremelt-kneaded in an extruder.

Examples of the α, β-unsaturated carboxylic acid or its derivative to beused for the introduction of the carboxylic acid group includeβ-unsaturated monocarboxylic acids such as acrylic acid and methacrylicacid; α,β-unsaturated dicarboxylic acids such as maleic acid, succinicacid, itaconic acid and phthalic acid; and α, β-unsaturatedmonocarboxylic acid esters such as glycidylacrylate, glycidylmethacrylate, hydroxyethyl acrylate and hydroxymethyl methacrylate. InEmbodiment (Y) of the present invention, adjacent carboxylic acid groupsintroduced into the block copolymer may form an acid anhydridestructure. Examples of the acid anhydride structure includeα,β-unsaturated dicarboxylic acid anhydrides such as maleic anhydride,succinic anhydride, itaconic anhydride and phthalic anhydride.

The block copolymer to be used in Embodiment (Y) typically has a weightaverage molecular weight of 50,000 to 500,000, particularly preferably120,000 to 450,000, further preferably 150,000 to 400,000.

If the weight average molecular weight is excessively great orexcessively small, or if the melt viscosity to be described below isexcessively high or excessively low, the resin composition fails to havehomogenous morphology with the block copolymer homogeneously dispersedin the PVA resin and, therefore, tends to have poorer mechanicalproperties.

The weight average molecular weight of the block copolymer is measuredby a gel permeation chromatography (GPC) based on a polystyrenecalibration standard.

The block copolymer typically has a melt viscosity of 100 to 3000 mPa·s,particularly preferably 300 to 2000 mPa·s, further preferably 800 to1500 mPa·s, as measured at 220° C. with a shearing speed of 122 sec⁻¹.

In Embodiment (Y), the block copolymer may include a single type ofblock copolymer, or may include plural types of block copolymers inorder to impart the resin composition with desired properties.

Commercially available examples of the block copolymer having thereactive functional group include TOUGHTECH M series (carboxylgroup-modified SEBS) available from Asahi Kasei Corporation, f-DYNARONavailable from JSR Corporation, and KRATON FG available from Shell JapanCo.

[Laminate Shaping Support Material According to Embodiment (Y)]

The laminate shaping support material according to Embodiment (Y)contains the PVA resin and the block copolymer. The proportion of thePVA resin is preferably 50 to 95 wt. %, more preferably 60 to 90 wt. %,particularly preferably 65 to 75 wt %, based on the total weight of thePVA resin and the block copolymer in the support material. If theproportion is less than 50 wt. %, the support material tends to have areduced water solubility. If the proportion is greater than 95 wt. %,the support material tends to have a reduced flexibility.

The proportion of the PVA resin is 50 to 95 wt. %, preferably 60 to 90wt. %, particularly preferably 70 to 80 wt. %, based on the overallweight of the support material. If the proportion is excessively small,the support material tends to have a significantly reduced watersolubility. If the proportion is excessively great, the support materialtends to have an insufficient flexibility.

The proportion of the block copolymer is preferably 5 to 50 wt. %, morepreferably 10 to 40 wt. %, particularly preferably 25 to 35 wt %, basedon the total weight of the PVA resin and the block copolymer. If theproportion is less than 5 wt. %, the support material tends to have aninsufficient flexibility. If the proportion is greater than 50 wt. %,the support material tends to have poorer forming stability with anexcessively high melt viscosity.

The proportion of the block copolymer is 5 to 50 wt. %, preferably 10 to40 wt. %, particularly preferably 20 to 30 wt. %, based on the overallweight of the support material. If the proportion is excessively small,the support material tends to have an insufficient flexibility. If theproportion is excessively great, the support material tends to havepoorer forming stability.

Since the support material is fed in the form of a strand to a head ofthe laminate shaping apparatus, the support material preferably has aproper rigidity for smooth feeding thereof. Further, the strand of thesupport material is often fed through a tube to the head of the laminateshaping apparatus. Therefore, the support material preferably has asurface highly slidable with respect to an interior surface of the tube.Accordingly, the surface of the support material is preferably smoothand free from tackiness for the smooth feeding of the strand of thesupport material to the head of the laminate shaping apparatus. Ingeneral, a strand surface of the PVA resin is highly hygroscopic andhence liable to be tacky. Therefore, a filler is preferably added to thesupport material in order to impart the strand of the support materialwith proper rigidity and to suppress the tackiness of the strand.

The filler may be an organic filler or an inorganic filler. Forexcellent heat stability, the inorganic filler is preferred. Examples ofthe inorganic filler include oxides, hydroxides, carbonates, sulfates,silicates, nitrides, carbon compounds and metals, among which thesilicates are preferred because they have no adverse influence on theheat stability of the support material. Examples of the silicatesinclude calcium silicate, talc, clay, mica, montmorillonite, bentonite,activated clay, sepiolite, imogolite, sericite, glass fibers, glassbeads and silica balloons, among which the talc is preferred because itimproves the surface smoothness of the support material and alleviatesthe tackiness of the support material. The filler preferably has aparticle size of 0.5 to 500 μm, more preferably 50 to 400 μm,particularly preferably 100 to 300 μm. The talc preferably has aparticle size of 0.5 to 10 μm, more preferably 1 to 5 μm, particularlypreferably 2 to 3 μm. If the particle size is excessively small, it willbe difficult to knead the filler in the resin. If the particle size isexcessively great, the support material tends to have a rough surfaceand a lower strength. Industrially preferred examples of the fillerinclude SG-95 and SG-200 available from Nippon Talc Co., Ltd., andLSM-400 available from Fuji Talc Industrial Co., Ltd. The particle sizeherein means a particle diameter D50 measured by a laser diffractionmethod. The proportion of the filler is preferably 1 to 40 wt. %, morepreferably 2 to 30 wt. %, particularly preferably 3 to 10 wt. %, basedon the weight of the support material. If the proportion of the filleris excessively small, the effect of the addition of the filler cannot beprovided. If the proportion of the filler is excessively great, thestrand of the support material tends to have a reduced surfacesmoothness and a reduced flexibility.

The support material may contain a plasticizer. In Embodiment (Y),however, the proportion of the plasticizer is preferably minimized inorder to improve the forming stability of the support material, and ispreferably not greater than 20 wt. %, more preferably not greater than10 wt. %, further preferably not greater than 1 wt. %, particularlypreferably not greater than 0.1 wt. %.

In addition to the aforementioned ingredients, as required, knownadditives such as an antioxidant, a colorant, an antistatic agent, a UVabsorber and a lubricant, and other thermoplastic resin may be added tothe resin composition. Specific examples of the other thermoplasticresin include olefin homopolymers and copolymers such as linearlow-density polyethylenes, low-density polyethylenes, medium-densitypolyethylenes, high-density polyethylenes, ethylene-vinyl acetatecopolymers, ionomers, ethylene-propylene copolymers, ethylene-α-olefin(C4 to C20 α-olefin) copolymers, ethylene-acrylate copolymers,polypropylenes, propylene-α-olefin (C4 to C20 α-olefin) copolymers,polybutenes and polypentenes, polycycloolefins, polyolefin resins in abroader sense such as obtained by graft-modifying any of these olefinhomopolymers and copolymers with an unsaturated carboxylic acid or anunsaturated carboxylate, polystyrene resins, polyesters, polyamides,copolymerized polyamides, polyvinyl chlorides, polyvinylidene chlorides,acrylic resins, vinyl ester resins, polyurethane elastomers, chlorinatedpolyethylenes and chlorinated polypropylenes.

As in Embodiment (X), the production method of the support material tobe used for the laminate shaping includes the steps of mixing theaforementioned ingredients in predetermined proportions, kneading theresulting mixture in a melted state with heating, extruding the mixtureinto a strand, cooling the strand and winding the strand around a reel.More specifically, the ingredients are fed as a mixture or separatelyinto a single screw or multi-screw extruder, heat-melted and kneaded,and extruded from a single-hole or multi-hole strand die into a 1.5- to3.0-mm diameter strand, which is in turn cooled with air or with waterto be solidified and then wound around the reel. The strand is requiredto have a stable diameter and have flexibility and toughness sufficientto prevent breakage even if being wound around the reel. Further, thestrand is required to have rigidity sufficient to ensure proper feed-outthereof to the head without delay in the laminate shaping.

[Laminate-Shaped Product Production Method and Laminate-Shaped Product]

A laminate-shaped product production method employing the inventivesupport material will be described.

A known laminate shaping apparatus may be used as the laminate shapingapparatus for the laminate shaping, as long as the apparatus includes aplurality of heads respectively adapted to extrude the model materialand the support material and is capable of performing a fusion laminateshaping process. Examples of the laminate shaping apparatus include dualhead type laminate shaping apparatuses such as CREATOR available fromFlashforge Co., Ltd., EAGLEED available from Reis Enterprise Co., Ltd.,MBOT Grid II available from 3D Systems Corporation and UPRINT SEavailable from Stratasys Ltd. Exemplary materials to be used as themodel material for forming a three-dimensional product include variousresins such as acrylonitrile butadiene styrene (ABS) resins, polylacticacids, polystyrenes, polyamides and polyethylenes, among which the ABSresins are mainly used from the viewpoint of melt-formability, heatstability and mechanical properties after solidification. The supportmaterial is required to have excellent adhesiveness to the ABS resins.

Like the support material, the model material is formed into a strand,which is in turn wound around a reel. The strands of the model materialand the support material are respectively fed to separate heads of thelaminate shaping apparatus, melted in the heads with heating, andapplied in a fluid state onto a stage from separate nozzles to bepressed against the stage and laid one over another. The meltingtemperatures in the heads are typically 150° C. to 220° C., and theextruding pressures are typically 200 to 1000 psi. The laminating pitchis typically 200 to 350 μm.

A laminate thus formed from the support material and the model materialis cooled to be solidified, and then the support material is removedfrom the laminate, whereby the intended laminate-shaped product isproduced. For example, the inventive support material is dissolved awayin water. To dissolve away the support material, the laminate may beimmersed in water or hot water contained in a container, or the supportmaterial may be washed away from the laminate with running water. Wherethe dissolution of the support material is achieved by immersing thelaminate in water, it is preferred to stir the water or apply ultrasonicwaves to the water in order to reduce the dissolution process time. Thetemperature of the water is preferably about 25° C. to about 80° C. Theweight of the water or the hot water to be used for the dissolution ofthe support material is about 10 to about 10000 times the weight of thesupport material. A characteristic feature of the inventive supportmaterial is that the support material can be easily dissolved away inwater at a relatively low temperature.

EXAMPLES

The present invention will hereinafter be described more specifically byway of examples thereof. It should be understood that the presentinvention be not limited to these examples within the scope of theinvention. In the examples, the term “part(s)” means part(s) by weight.

Examples of Embodiment (X) Example 1 (i) Preparation of1,2-Diol-Containing PVA Resin (1)

In a reaction vessel provided with a reflux condenser, a dropping funneland a stirrer, 10% of 68.5 parts of vinyl acetate and 20.5 parts ofmethanol were first fed, and the rest of the vinyl acetate and 11.0parts (7.2 mol % with respect to the amount of vinyl acetate to be fed)of 3,4-diacetoxy-1-butene were fed dropwise at constant rates in 9hours. Then, 0.3 mol % (with respect to the amount of the fed vinylacetate) of azobisisobutyronitrile was fed into the reaction vessel. Inturn, the temperature was raised while the resulting mixture was stirredin a nitrogen stream, thereby initiating polymerization. When thepolymerization degree of vinyl acetate reached 90%, a predeterminedamount of m-dinitrobenzene was added to the reaction vessel to terminatethe polymerization. Subsequently, methanol vapor was blown into thereaction vessel, whereby unreacted vinyl acetate monomer was removed outof the reaction vessel. Thus, a copolymer was prepared in the form of amethanol solution.

The methanol solution was further diluted with methanol to aconcentration of 45 wt. %, and fed into a kneader. Then, a methanolsolution of sodium hydroxide having a sodium concentration of 2 wt. %was added in a proportion of 10.5 mmol based on a total amount of 1 molof a vinyl acetate structural unit and a 3,4-diacetoxy-1-butenestructural unit of the copolymer with the solution temperature kept at35° C., and the copolymer was saponified for 4 hours. As thesaponification proceeded, a saponification product was precipitated.When the saponification product was obtained in a particulate form, thesaponification product was separated by a solid/liquid separationprocess. The resulting saponification product was thoroughly rinsed withmethanol, and dried at 70° C. for 12 hours in a hot air dryer. Thus, anintended 1,2-diol-containing PVA resin (1) was prepared.

The 1,2-did-containing PVA resin (1) thus prepared had a saponificationdegree of 99.0 mol % as determined by measuring an alkali consumptionrequired for hydrolysis of vinyl acetate remaining in the resin and thestructural unit of 3,4-diacetoxy-1-butene. The PVA resin (1) had anaverage polymerization degree of 360 as determined by analysis inconformity with JIS K6726, and a melting point of 175° C. as measured bya differential thermal analyzer DSC. The content of the 1,2-diolstructural unit represented by the formula (1) was 7.2 mol % ascalculated from an integration value measured by ¹H-NMR (300 MHz protonNMR using a d6-DMSO solution and an internal standard oftetramethylsilane at 50° C.)

The PVA resin (1) had a heat (ΔH) of fusion of 21.5 J/g at its meltingpoint as measured by means of a Perkin-Elmer's input compensation typedifferential scanning calorimeter “Diamond DSC” by sealing 5 mg of asample in a measurement pan, increasing the temperature at a temperatureincrease rate of 10° C./min from −30° C. to 215° C., immediatelythereafter reducing the temperature at a temperature decrease rate of10° C./min to −30° C. and increasing the temperature again at atemperature increase rate of 10° C./min to 230° C.

(ii) Production of Support Material

The 1,2-diol-containing PVA resin (1) was fed into a twin screwextruder, melted and kneaded under the following conditions and extrudedinto a strand having a diameter of 1.75 mm, and the strand was cooled ona belt and wound around a reel. Thus, a support material was produced.The support material was evaluated in the following manner. The resultsof the evaluation are shown in Table 1.

Extruder: Available from Technovel Corporation, and having a diameter of15 mm and an L/D ratio of L/D=60Extruding temperature: C1/C2/C3/C4/C5/C6/C7/C8/D=150° C./170° C./180°C./190° C./200° C./210° C./230° C./230° C./230° C.Rotation speed: 200 rpmDischarge amount: 1.5 kg/hour

(iii) Evaluation of Support Material [Shape Stability]

A plate of the support material was prepared by means of an injectionmolding machine PS60E12ASE available from Nissei Ltd. by using a platemold having a size of 5.0×2.5 cm and a thickness of 2 mm and employingan injection temperature of 210° C., an injection speed of 50%, aninjection pressure of 60%, a mold temperature of 70° C. and a coolingperiod of 30 seconds. The plate was placed on a hot plate at 80° C. tobe heated. After 3.0 g of an ABS resin TOYORAC Grade 600-309 availablefrom Toray Corporation was extruded in a melted state onto the supportmaterial plate at 230° C. at a discharge rate of 0.5 kg/hour by means ofa 15=1) single screw extruder, the support material plate was removedfrom the hot plate and sufficiently cooled in a 25° C. atmosphere. Whenthe ABS resin was thereafter peeled off from the support material plate,the state of the surface of the plate was visually checked, and ratedbased on the following criteria:

Excellent (∘∘): The plate was not deformed at all.Acceptable (∘): The plate was slightly deformed.Unacceptable (x): The plate was apparently deformed.

[Adhesiveness to Model Material]

An ABS resin TOYORAC Grade 600-309 available from Toray Corporation wasextruded to be formed into a single layer film having a thickness of 30μm, and the support material was laid over the single layer film to athickness of 5 μm under the following conditions by an extrusion coatingmethod. The resulting double layer film was cut to a width of 15 mm, anda T-peeling test was performed on the resulting strip at a peeling rateof 100 mm/min in conformity with JIS K6854-3 for evaluation of thesupport material for adhesiveness. Extruder: Available from TechnovelCorporation, and having a diameter of 15 mm and an L/D ratio of L/D=60

Die: A 30-cm width coat hanger die having a lip opening size of 0.35 mm

Extruding temperature: C1/C2/C3/C4/C5/C6/C7/C8/D=150° C./170° C./180°C./190° C./200° C./210° C./230° C./230° C./230° C. Discharge amount: 0.5kg/hour

Example 2 (i) Preparation of 1,2-Diol-Containing PVA Resin (2)

In substantially the same manner as in Example 1, 40% of 72.1 parts ofvinyl acetate and 21.6 parts of methanol were first fed in a reactionvessel, and the rest of the vinyl acetate and 6.3 parts of3,4-diacetoxy-1-butene were fed dropwise at constant rates in 8 hours.Then, 0.16 mol % (with respect to the amount of the fed vinyl acetate)of azobisisobutyronitrile was fed in the reaction vessel. In turn, thetemperature was raised while the resulting mixture was stirred in anitrogen stream, thereby initiating polymerization. When thepolymerization degree of vinyl acetate reached 90%, a predeterminedamount of m-dinitrobenzene was added to the reaction vessel to terminatethe polymerization. Subsequently, methanol vapor was blown into thereaction vessel, whereby unreacted vinyl acetate monomer was removed outof the reaction vessel. Thus, a copolymer was prepared in the form of amethanol solution.

The methanol solution was further diluted with methanol to aconcentration of 55 wt. %, and fed into a kneader. Then, a methanolsolution of sodium hydroxide having a sodium concentration of 2 wt. %was added in a proportion of 3.0 mmol based on a total amount of 1 molof a vinyl acetate structural unit and a 3,4-diacetoxy-1-butenestructural unit of the copolymer with the solution temperature kept at35° C., whereby the copolymer was saponified. As the saponificationproceeded, a saponification product was precipitated. When thesaponification product was obtained in a particulate form, thesaponification product was separated by a solid/liquid separationprocess. The resulting saponification product was thoroughly rinsed withmethanol, and dried in a hot air dryer. Thus, an intended1,2-diol-containing PVA resin (2) was prepared.

The 1,2-diol-containing PVA resin (2) thus prepared had a saponificationdegree of 78.0 mol %, an average polymerization degree of 450, a1,2-diol structural unit content of 4.5 mol %, a melting point of 143°C., and a heat (ΔH) of fusion of 14.3 J/g.

In the same manner as in Example 1, the 1,2-diol-containing PVA resin(2) thus prepared was kneaded by means of a twin screw extruder, andformed into a strand-shaped support material, which was in turnevaluated.

Comparative Example 1 (i) Preparation of 1,2-Diol-Containing PVA Resin(3)

In a reaction vessel provided with a reflux condenser, a dropping funneland a stirrer, 27.1 parts (40 wt. % of the total feed amount) of vinylacetate, 14.2 parts of methanol and 7.2 parts (40 wt. % of the totalfeed amount) of 3,4-diacetoxy-1-butene were first fed, and then 0.06 mol% (with respect to the amount of the fed vinyl acetate) ofazobisisobutyronitrile was fed. In turn, the temperature was raisedwhile the resulting mixture was stirred in a nitrogen stream, therebyinitiating polymerization.

Further, 40.7 parts (60 wt. % of the total feed amount) of vinyl acetateand 10.8 parts (60 wt. % of the total feed amount) of3,4-diacetoxy-1-butene were fed dropwise at constant rates in thereaction vessel in 15 hours, during which 0.04 mol % (with respect tothe amount of the fed vinyl acetate) of azobisisobutyronitrile wasadditionally fed dividedly in two parts into the reaction vessel and thepolymerization was continued. When the polymerization degree of vinylacetate reached 90%, a predetermined amount of m-dinitrobenzene wasadded to the reaction vessel to terminate the polymerization.Subsequently, methanol vapor was blown into the reaction vessel, wherebyunreacted vinyl acetate was removed out of the reaction vessel. Thus, acopolymer was prepared in the form of a methanol solution.

Then, the methanol solution was further diluted with methanol to aconcentration of 55 wt. %, and fed into a kneader. Then, a methanolsolution of sodium hydroxide having a sodium concentration of 2 wt. %was added in a proportion of 3.5 mmol based on a total amount of 1 molof a vinyl acetate structural unit and a 3,4-diacetoxy-1-butenestructural unit of the copolymer with the solution temperature kept at35° C., whereby the copolymer was saponified. As the saponificationproceeded, a saponification product was precipitated. When thesaponification product was obtained in a particulate form, thesaponification product was filtered out. The resulting saponificationproduct was thoroughly rinsed with methanol, and dried in a hot airdryer. Thus, an intended 1,2-diol-containing PVA resin (3) was prepared.

The 1,2-diol-containing PVA resin (3) thus prepared had a saponificationdegree of 88.0 mol % as determined by measuring an alkali consumptionrequired for hydrolysis of remaining vinyl acetate and3,4-diacetoxy-1-butene. Further, the PVA resin (3) had an averagepolymerization degree of 450 as determined by analysis in conformitywith JIS K6726, and a 1,2-diol structural unit content of 12 mol %.

Measurement was performed on the thus prepared 1,2-diol-containing PVAresin (3) by means of a differential scanning calorimeter, and it wasfound that the 1,2-diol-containing PVA resin (3) was an amorphouspolymer having no melting point peak without heat of fusion. In the samemanner as in Example 1, the resin was kneaded by means of a twin screwextruder, and formed into a strand-shaped support material, which was inturn evaluated.

The evaluation results are also shown in Table 1.

TABLE 1 Comparative Example 1 Example 2 Example 1 PVA resin Type of PVAPVA (1) PVA (2) PVA (3) Amount (mol %) of 1,2-diol 7.2 4.5 12Polymerization degree 360 450 450 Saponification degree (mol %) 99 78 88ΔH (J/g) 21.5 14.3 N.D. Acid-modified SEBS Not Not Not containedcontained contained Evaluation Shape stability ∘∘ ∘ x Adhesiveness tomodel material 410 mN/ 160 mN/ 30 mN/15 mm 15 mm 15 mm

As apparent from the above results, the support materials each includinga 1,2-diol-containing PVA resin having a heat ΔH of fusion fallingwithin the specific range are more excellent in shape stability and moreuseful, with an adhesive force of higher than 100 mN/15 mm with respectto the model material, than the support material (Comparative Example 1)including a 1,2-diol-containing PVA resin having a heat ΔH of fusionfalling outside the specific range.

Example 3

First, 70 parts of the 1,2-diol-containing PVA resin (1) prepared inExample 1 and 30 parts of a styrene/ethylene/butylene block copolymer(SEGS) having a carboxyl group (TOUGHTECH M1911 available from AsahiKasei Corporation and having an acid value of 2 mg CH₃ONa/g) as a blockcopolymer were dry-blended. Then, the resulting mixture was fed into atwin screw extruder and melt-kneaded. The resulting resin compositionwas extruded into a strand having a diameter of 1.75 mm, and the strandwas cooled on a belt with air and wound around a reel. Thus, a supportmaterial was produced, and evaluated in the aforementioned manner. Theresults of the evaluation are shown in Table 2.

Example 4

First, 70 parts of the 1,2-diol-containing PVA resin (2) prepared inExample 2 and 30 parts of a styrene/ethylene/butylene block copolymer(SEGS) having a carboxyl group (TOUGHTECH M1911 available from AsahiKasei Corporation and having an acid value of 2 mg CH₃ONa/g) as a blockcopolymer were dry-blended. Then, a support material was produced andevaluated in the same manner as in Example 3.

The results of the evaluation are shown in Table 2.

TABLE 2 Example 3 Example 4 PVA resin Type of PVA PVA (1) PVA (2) Amount(mol %) of 1,2-diol 7.2 4.5 Polymerization degree 360 450 Saponificationdegree (mol %) 99 78 ΔH (J/g) 21.5 14.3 Acid-modified SEBS ContainedContained Evaluation Shape stability ∘∘ ∘ Adhesiveness to model material560 mN/15 mm 630 mN/15 mm

As apparent from the above results, the support materials each includinga 1,2-diol-containing PVA resin having a heat ΔH of fusion fallingwithin the specific range are excellent in shape stability and usefulwith an adhesive force of higher than 300 mN/15 mm with respect to themodel material.

Examples of Embodiment (Y) Example 5 (i) Preparation of PVA Resin (5)

In a reaction can provided with a reflux condenser, a dropping funneland a stirrer, 100 parts of vinyl acetate and 100 parts of methanol werefirst fed, and 0.15 mol % (with respect to the amount of the fed vinylacetate) of azobisisobutyronitrile was fed. Then, the temperature wasraised while the resulting mixture was stirred in a nitrogen stream,thereby initiating polymerization. After a lapse of 5 hours from theinitiation of the polymerization, 0.05 mol % of azobisisobutyronitrilewas added to the reaction can. When the polymerization degree of vinylacetate reached 85%, a predetermined amount of m-dinitrobenzene wasadded to the reaction can to terminate the polymerization. Subsequently,methanol vapor was blown into the reaction can to be distilled, wherebyunreacted vinyl acetate monomer was removed out of the reaction can.Thus, a copolymer was prepared in the form of a methanol solution.

Subsequently, the solution was further diluted with methanol to aconcentration of 50 wt. %, and fed into a kneader. Then, a methanolsolution of sodium hydroxide having a sodium concentration of 2 wt. %was added in a proportion of 4.3 mmol based on 1 mol of a vinyl acetatestructural unit of the copolymer with the solution temperature kept at35° C., whereby the copolymer was saponified. As the saponificationproceeded, a saponification product was precipitated. When thesaponification product was obtained in a particulate form, 1.0equivalent of sodium hydroxide containing acetic acid for neutralizationwas added to the reaction can. Then, the resulting saponificationproduct was filtered out, thoroughly rinsed with methanol, and dried ina hot air dryer. Thus, an intended PVA resin (5) was prepared.

The PVA resin (5) thus prepared had a saponification degree of 88 mol %as determined by measuring an alkali consumption required for hydrolysisof remaining vinyl acetate, and an average polymerization degree of 500as determined by analysis in conformity with JIS K6726.

(ii) Production of Support Material

First, 70 parts of the PVA resin (5) and 30 parts of astyrene/ethylene/butylene block copolymer (SEBS) having a carboxylicacid group (TOUGHTECH M1911 available from Asahi Kasei Corporation andhaving an acid value of 2 mg CH₃ONa/g) as a block polymer weredry-blended. Then, the resulting mixture was fed into a twin screwextruder, and melt-kneaded under the following conditions. The resultingresin composition was extruded into a strand having a diameter of 1.75mm, and the strand was cooled on a belt with air and wound around areel. Thus, a support material was produced, and evaluated in theaforementioned manner. The results of the evaluation are shown in Table3. Extruder: Available from Technovel Corporation, and having a diameterof 15 mm and an L/D ratio of L/D=60 Extruding temperature:C1/C2/C3/C4/C5/C6/C7/C8/D=150° C./170° C./180° C./190° C./200° C./210°C./220° C./220° C./220° C. Rotation speed: 200 rpm Discharge amount: 1.5kg/hour

(iii) Evaluation of Support Material [Peelability]

It is important that the support material is not torn off even if beingstretched for peeling thereof. It is considered that a support materialhaving a higher breaking stress has a higher toughness.

After the laminate shaping with the use of the support material, thesupport material is peeled off from a shaped product of a modelmaterial. Without sufficient flexibility, however, the support materialcannot be properly peeled off from the shaped product of the modelmaterial. Without sufficient toughness, the support material will betorn off when being stretched for peeling thereof. Therefore, thesupport material cannot be efficiently peeled off. Thus, the supportmaterial is required to have flexibility and toughness for properpeelability. For this reason, flexibility evaluation and toughnessevaluation were performed in the following manner:

<Flexibility Evaluation>

A strand of the support material maintained in a dry state was cut to 30cm, and bent around a cylindrical iron rod having a diameter of 5 cmwith a 10-cm long end portion thereof left. It was checked whether ornot the strand was broken until it was wound around the rod once. Thisoperation was performed on 5 strands, and the support material wasevaluated based on the following criteria:

Good (∘): Not more than 1 strand was broken.Acceptable (A): 2 to 4 strands were broken.Unacceptable (x): All the 5 strands were broken.

<Toughness Evaluation>

A strand of the support material maintained in a dry state was cut to 10cm, and a tensile test was performed on the cut strand by means of atensile tester by stretching the strand at a stretching speed of 10mm/min with a gage distance of 30 mm. At this time, the breaking stresswas determined.

[Forming Stability]

The diameters of the produced strand were measured at ten points spaced20 cm from each other by means of a caliper, and an average stranddiameter was calculated. Where the cross section of the strand was not aperfect circle, the greatest diameter was measured. The strand wasevaluated based on the following criteria indicating the relationshipbetween the calculated average diameter and the diameters measured at 10points.

Excellent (∘∘): All the measured diameters fell within a range of theaverage diameter±0.05 mm.Good (∘): One or more of the measured diameters fell outside the rangeof the average diameter±0.05 mm, and all the measured diameters fellwithin a range of the average diameter±0.15 mm.Acceptable (A): One or more of the measured diameters fell outside therange of the average diameter±0.15 mm, and all the measured diametersfell within a range of the average diameter±0.25 mm.Unacceptable (x): One or more of the measured diameters fell outside therange of the average diameter±0.25 mm.

The support material is extruded in a melted state from a nozzle forshaping. If the diameter of the support material extruded from thenozzle is unstable, however, the shaping is not stabilized, making itimpossible to shape an intended product with higher reproducibility.Since the strand of the support material is formed by extrusion in themelted state, the stable diameter of the strand means that the supportmaterial is stably extruded in the laminate shaping. Therefore, thesupport material that ensures the production of the shaped product withhigher reproducibility is excellent in forming stability in theproduction of the strand with a stable strand diameter.

[Smoothness of Strand]

The surface of the strand of the support material prepared in theaforementioned manner was visually and tactilly evaluated based on thefollowing criteria:

Excellent (∘∘): The surface was smooth, and free from tackiness.Good (∘): The surface was smooth and tacky.Acceptable (A): The surface was slightly rough and tacky.Unacceptable (x): The surface was very rough.

Example 6

A PVA resin (6) having a saponification degree of 72 mol % was preparedin substantially the same manner as in Example 5 by reducing thesaponification period. Then, a support material was produced andevaluated in the same manner.

Example 7

A support material was produced in substantially the same manner as inExample 5, except that 85 parts of the PVA resin (5) and 15 parts of theblock copolymer were kneaded and extruded. Then, the support materialwas evaluated in the same manner.

Example 8

The support material was produced in substantially the same manner as inExample 7, except that 15 parts of TOUGHTECH M1913 (available from AsahiKasei Corporation and having an acid value of 10 mg CH₃ONa/g) was usedas the block copolymer.

Example 9 (i) Preparation of 1,2-Diol-Containing PVA Resin (7)

In a reaction can provided with a reflux condenser, a dropping funneland a stirrer, 68.0 parts of vinyl acetate, 23.8 parts of methanol and8.2 parts of 3,4-diacetoxy-1-butene were first fed, and then 0.3 mol %(with respect to the amount of the fed vinyl acetate) ofazobisisobutyronitrile was fed. In turn, the temperature was raisedwhile the resulting mixture was stirred in a nitrogen stream, therebyinitiating polymerization. When the polymerization degree of vinylacetate reached 90%, a predetermined amount of m-dinitrobenzene wasadded to the reaction can to terminate the polymerization. Subsequently,methanol vapor was blown into the reaction can, whereby unreacted vinylacetate monomer was removed out of the reaction can. Thus, a copolymerwas prepared in the form of a methanol solution.

Then, the methanol solution was further diluted with methanol to aconcentration of 55 wt. %, and fed into a kneader. Then, a methanolsolution of sodium hydroxide having a sodium concentration of 2 wt. %was added in a proportion of 3.5 mmol based on a total amount of 1 molof a vinyl acetate structural unit and a 3,4-diacetoxy-1-butenestructural unit of the copolymer with the solution temperature kept at35° C., whereby the copolymer was saponified. As the saponificationproceeded, a saponification product was precipitated. When thesaponification product was obtained in a particulate form, thesaponification product was separated by a solid/liquid separationprocess. The resulting saponification product was thoroughly rinsed withmethanol, and dried in a hot air dryer. Thus, an intended1,2-diol-containing PVA resin (7) was prepared.

The 1,2-diol-containing PVA resin (7) thus prepared had a saponificationdegree of 88.0 mol %, and a polymerization degree of 450. The content ofthe 1,2-diol structural unit represented by the above formula was 6 mol% as calculated from an integration value measured by ¹H-NMR (300 MHzproton NMR using a d6-DMSO solution and an internal standard oftetramethylsilane at 50° C.).

A support material was produced in substantially the same manner as inExample 5, except that the 1,2-diol-containing PVA resin (7) was usedinstead of the PVA resin (5). Then, the support material was evaluated.

Example 10 (i) Preparation of 1,2-Diol-Containing PVA Resin (8)

In a reaction can provided with a reflux condenser, a dropping funneland a stirrer, 85 g of vinyl acetate (equivalent to an initial feedamount of 10 wt. % of the total feed amount), 460 g of methanol and 13.6g (7.2 mol % with respect to the amount of the fed vinyl acetate) of3,4-diacetoxy-1-butene were first fed, and then 0.2 mol % (with respectto the amount of the fed vinyl acetate) of azobisisobutyronitrile wasfed. In turn, the temperature was raised while the resulting mixture wasstirred in a nitrogen stream, thereby initiating polymerization. After alapse of 0.5 hours from the initiation of the polymerization, vinylacetate (90 wt. % of the total feed amount) was added dropwise to thereaction can (at a dropping speed of 95.6 g/hr) in 8 hours. After lapsesof 2.5 hours and 4.5 hours from the initiation of the polymerization,0.1 mol % of azobisisobutyronitrile was added to the reaction can. Whenthe polymerization degree of vinyl acetate reached 85%, a predeterminedamount of m-dinitrobenzene was added to the reaction can to terminatethe polymerization. Subsequently, methanol vapor was blown into thereaction can to be distilled, whereby unreacted vinyl acetate monomerwas removed out of the reaction can. Thus, a copolymer was prepared inthe form of a methanol solution.

Then, the methanol solution was further diluted with methanol to aconcentration of 50 wt. %, and fed into a kneader. Then, a methanolsolution of sodium hydroxide having a sodium concentration of 2 wt. %was added in a proportion of 9 mmol based on a total amount of 1 mol ofa vinyl acetate structural unit and a 3,4-diacetoxy-1-butene structuralunit of the copolymer with the solution temperature kept at 35° C.,whereby the copolymer was saponified. As the saponification proceeded, asaponification product was precipitated. When the saponification productwas obtained in a particulate form, the 2 wt. % sodium hydroxidemethanol solution was added in a proportion of 4 mmol based on a totalamount of 1 mol of the vinyl acetate structural unit and the3,4-diacetoxy-1-butene structural unit, whereby the saponificationfurther proceeded. Thereafter, acetic acid was added in an amount of 0.8equivalents based on the amount of the sodium hydroxide forneutralization. Then, the resulting saponification product was filteredoff, thoroughly rinsed with methanol, and dried in a hot air dryer.Thus, an intended PVA resin (8) was prepared.

The PVA resin (8) thus prepared had a saponification degree of 99.0 mol% as determined by analysis of an alkali consumption required forhydrolysis of remaining vinyl acetate and 3,4-diacetoxy-1-butene.Further, the PVA resin (8) had an average polymerization degree of 360as measured by analysis in conformity with JIS 1(6726, and a 1,2-dialstructural unit content of 7.2 mol %.

A support material was produced in substantially the same manner as inExample 5, except that the 1,2-dial-containing PVA resin (8) prepared inthe aforementioned manner was used instead of the PVA resin (5). Then,the support material was evaluated.

Example 11

A support material was produced by feeding 66.5 parts of the1,2-dial-containing PVA resin (8) prepared in Example 10, 28.5 parts ofthe carboxyl group-containing SEBS used in Example 5 and 5 parts ofultrafine talc SG-95 (having a particle diameter of 2.5 μm) availablefrom Nippon Talc Co., Ltd. as a filler into a twin screw extruder. Then,the support material was evaluated.

Example 12

A support material was produced in substantially the same manner as inExample 11, except that 56 parts of the 1,2-dial-containing PVA resin(8), 24 parts of the carboxyl group-containing SEBS and 20 parts of talc(filler) were used. Then, the support material was evaluated.

Comparative Example 2

A support material was produced in substantially the same manner as inExample 5, except that a carboxyl group-free SEBS (TOUGHTECH H1041available from Asahi Kasei Corporation and having an acid value of 0 mgCH₃ONa/g) provided instead of the block copolymer of Example 5 and thePVA resin (5) were fed into a twin screw extruder and melt-kneaded.Then, the support material was evaluated in the same manner.

The results of the evaluation are also shown below in Table 3.

TABLE 3 Example Example Comparative Example 5 Example 6 Example 7Example 8 Example 9 10 11 Example 12 Example 2 Support material PVAresin Side chain 1,2-diol amount (mol %) 0 0 0 0 6 7.2 7.2 7.2 0Polymerization degree 500 500 500 500 450 360 360 360 500 Saponificationdegree (mol %) 88 72 88 88 88 99 99 99 88 Proportion (parts) 70 70 85 8570 70 66.5 56 70 Block copolymer Proportion (parts) 30 30 15 15 30 3028.5 24 30 Acid value 2 2 2 10 2 2 2 2 0 Filler Proportion (parts) 0 0 00 0 0 5 20 0 Evaluation Peelability Flexibility ∘ ∘ Δ Δ ∘ ∘ ∘ Δ xToughness N/mm² 46 44 58 62 72 64 60 43 12 Forming stability Stranddiameter stability Δ Δ ∘ ∘ ∘∘ ∘∘ ∘∘ ∘∘ x Smoothness of strand Surfacestate of strand ∘ Δ ∘ ∘ ∘ ∘ ∘∘ ∘∘ Δ

As apparent from the above results, the support materials each includinga PVA resin and a block copolymer including a polymer block of anaromatic vinyl compound and a polymer block of a conjugated dienecompound and/or a block of a hydrogenated conjugated diene compound andhaving a functional group reactive with a hydroxyl group are moreexcellent in peelability and forming stability, and more useful forfusion laminate shaping than the support material (Comparative Example2) including a PVA resin and a block copolymer having no functionalgroup reactive with a hydroxyl group.

While specific forms of the embodiments of the present invention havebeen shown in the aforementioned inventive examples, the inventiveexamples are merely illustrative of the invention but not limitative ofthe invention. It is contemplated that various modifications apparent tothose skilled in the art could be made within the scope of theinvention.

The inventive laminate shaping support materials are excellent in shapestability, adhesiveness to a model material, peelability and formingstability, and can be advantageously used as support materials for thefusion laminate shaping process.

What is claimed is:
 1. A method of forming a resin composition into a laminate-shaping support material comprising, heat-melting a resin composition comprising a polyvinyl alcohol resin including a structural unit with a side chain having a primary hydroxyl group, and having a melting point heat of fusion of 10 to 30 J/g; wherein the heat of fusion is measured by using a differential scanning calorimeter at a temperature increase rate of 10° C./min, and the heat of fusion is calculated based on a heat absorption peak area observed at the melting point in the temperature increase as heat ΔH (J/g) of fusion; and wherein, in an analysis chart in which an abscissa axis is defined as an axis of temperature, the heat absorption peak area is an area enclosed by a base line and a heat absorption peak, the base line being defined as a straight line connecting a point A at a temperature higher by 5° C. than an end point of the absorption peak of a curve and a point B at a temperature lower by 40° C. than an apex of the heat absorption peak of the curve; and forming the heat-melted resin composition into a laminate-shaping support material.
 2. The method according to claim 1, wherein the side chain having a primary hydroxyl is a 1,2-diol structure.
 3. The method according to claim 2, wherein the structural unit with a side chain having a primary hydroxyl group is a structural unit represented by the following formula (1):

wherein R¹, R² and R³ are independently each a hydrogen atom or a C1 to C4 alkyl group, X is a single bond or a bonding chain, R⁴ is independently a hydrogen atom or a C1 to C4 alkyl group, and R⁵ and R⁶ are independently each a hydrogen atom.
 4. A method for forming a laminate-shaped product comprising: laying a layer of a laminate-shaping support material and a layer of a model material one on another in a fluid state; solidifying the support material and the model material; and removing the support material, wherein the laminate-shaping support material consists of a resin composition comprising a polyvinyl alcohol resin including a structural unit with a side chain having a primary hydroxyl group, and having a melting point heat of fusion of 10 to 30 J/g; wherein the heat of fusion is measured by using a differential scanning calorimeter at a temperature increase rate of 10° C./min, and the heat of fusion is calculated based on a heat absorption peak area observed at the melting point in the temperature increase as heat ΔH (J/g) of fusion; and wherein, in an analysis chart in which an abscissa axis is defined as an axis of temperature, the heat absorption peak area is an area enclosed by a base line and a heat absorption peak, the base line being defined as a straight line connecting a point A at a temperature higher by 5° C. than an end point of the absorption peak of a curve and a point B at a temperature lower by 40° C. than an apex of the heat absorption peak of the curve.
 5. A laminate-shaping support material comprising a resin composition comprising a polyvinyl alcohol resin, and a block copolymer including a polymer block of an aromatic vinyl compound, at least one of a polymer block of a conjugated diene compound and a block of a hydrogenated conjugated diene compound, and a functional group reactive with a hydroxyl group.
 6. A laminate comprising: the laminate-shaping support material according to claim 5 and a model material, wherein a layer of the laminate-shaping support material and a layer of the model material are laid one on another in a fluid state.
 7. A method of producing a laminate-shaped product comprising: laying a layer of the laminate-shaping support material according to claim 5 and a layer of a model material one on another in a fluid state; solidifying the support material and the model material; and removing the support material.
 8. The laminate-shaping support material according to claim 5, wherein the block copolymer has an acid value of 0.5 to 20 mg CH₃ONa/g. 